content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * ----------------------
   * DefaultKeyedValue.java
   * ----------------------
   * (C) Copyright 2002-2012, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes:
   * --------
   * 31-Oct-2002 : Version 1 (DG);
   * 13-Mar-2003 : Added equals() method, and implemented Serializable (DG);
   * 18-Aug-2003 : Implemented Cloneable (DG);
   * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.base (DG);
   * 15-Sep-2004 : Added PublicCloneable interface (DG);
   * ------------- JFREECHART 1.0.x ---------------------------------------------
   * 11-Jun-2007 : Added toString() method to help with debugging (DG);
   * 15-Feb-2008 : Prevent null key (DG);
   * 07-Apr-2008 : Removed to-do item (DG);
   * 17-Jun-2012 : Removed JCommon dependencies (DG);
   *
   */
  
  package org.jfree.data;
  
  import java.io.Serializable;
  
  import org.jfree.chart.util.PublicCloneable;
  
  /**
   * A (key, value) pair.  This class provides a default implementation
   * of the {@link KeyedValue} interface.
   */
  public class DefaultKeyedValue implements KeyedValue, Cloneable,
          PublicCloneable, Serializable {
  
      /** For serialization. */
      private static final long serialVersionUID = -7388924517460437712L;
  
      /** The key. */
      private Comparable key;
  
      /** The value. */
      private Number value;
  
      /**
       * Creates a new (key, value) item.
       *
       * @param key  the key (should be immutable, <code>null</code> not
       *         permitted).
       * @param value  the value (<code>null</code> permitted).
       */
      public DefaultKeyedValue(Comparable key, Number value) {
          if (key == null) {
              throw new IllegalArgumentException("Null 'key' argument.");
          }
          this.key = key;
          this.value = value;
      }
  
      /**
       * Returns the key.
       *
       * @return The key (never <code>null</code>).
       */
      @Override
      public Comparable getKey() {
          return this.key;
      }
  
      /**
       * Returns the value.
       *
       * @return The value (possibly <code>null</code>).
       */
      @Override
      public Number getValue() {
          return this.value;
      }
  
      /**
       * Sets the value.
       *
       * @param value  the value (<code>null</code> permitted).
       */
      public synchronized void setValue(Number value) {
          this.value = value;
      }
  
      /**
       * Tests this key-value pair for equality with an arbitrary object.
       *
       * @param obj  the object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof DefaultKeyedValue)) {
              return false;
          }
          DefaultKeyedValue that = (DefaultKeyedValue) obj;
  
          if (!this.key.equals(that.key)) {
              return false;
          }
          if (this.value != null
                  ? !this.value.equals(that.value) : that.value != null) {
              return false;
          }
          return true;
      }
  
      /**
       * Returns a hash code.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          int result;
          result = (this.key != null ? this.key.hashCode() : 0);
          result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
          return result;
      }
  
      /**
       * Returns a clone.  It is assumed that both the key and value are
       * immutable objects, so only the references are cloned, not the objects
       * themselves.
       *
       * @return A clone.
       *
       * @throws CloneNotSupportedException Not thrown by this class, but
       *         subclasses (if any) might.
       */
      @Override
      public Object clone() throws CloneNotSupportedException {
          DefaultKeyedValue clone = (DefaultKeyedValue) super.clone();
          return clone;
      }
  
      /**
       * Returns a string representing this instance, primarily useful for
       * debugging.
       *
       * @return A string.
       */
      @Override
      public String toString() {
          return "(" + this.key.toString() + ", " + this.value.toString() + ")";
      }
  
  }
  